1. Field of the Invention
The present invention relates to a semiconductor light-emitting device such as a light-emitting diode (LED), and in particular, relates to a technique for enhancing light extraction in a semiconductor light-emitting device.
2. Description of the Related Art
The efficiency and output of LEDs and other semiconductor light-emitting devices are increasing owing to technological advances in recent years. However, with the increase in output, the amount of heat generated from the light-emitting element has also increased, and the resulting decrease in reliability is becoming an issue. In order to solve this problem, there have been proposed LEDs of a so-called thin-film structure, in which the growth substrate, used for crystal growth, having a relatively low thermal conductivity is removed, and the semiconductor layer is instead supported by a member having a relatively high thermal conductivity. According to the thin-film structure, the heat dissipation performance of the light-emitting element is improved, and an enhancement of the light extraction efficiency can be expected by the removal of the growth substrate. The laser lift-off (LLO) method, in which laser is directed from the reverse-surface side of the growth substrate and GaN is caused to degrade, is known as an example of a method for separating the growth substrate from a semiconductor film containing a GaN-based semiconductor crystal.